Tool controlling mechanism for machine tools



1932- F. H. BOGART TQUL CONTROLLING MECHANISM FOR MACHINE TOOLS Filed Jan. so, 1928 4 Sheets-Sheet 1 Feb. 23, 1932. F. H. BOGART TOOL CONTROLLING MECHANISM FOR MACHINE TOOLS Filed Jan. 30. 1928 4 Sheets-$heet 2 gwuantoz fan/3 [Ill]:

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Feb. 23,1932. F. H. BOGART TOOL CONTROLLING MECHANISM FOR MACHINE TOO LS Filed Jan. 4 Sheets-Sheet 4 Patented Feb. 23, 1932 fi l TES PATENT OFFICE FRED Ill. lBlIlG-ART, OF CLEVELAND HEIGHTS, OHIO, ASSIGNOR TO THE WARNER & ElW'ASEY COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO TOOL CONTROLLING MEOHAI'TISM FOR MACHINE TOOLS Application filed. January 30, 1928. Serial No. 250,454.

This invention relates to machine tools and has for one of its objects to provide certain iniproveinen s by which there is obtained an automatic withdrawal of the tool or tools from the work at the completion of the cut and the automatic restoration of the tool or tools to cutting position after the main tool slide ha. been retracted a predetermined distance from the work holding member so that the tool or tools are tree of the work.

A turther object is to provide an improved means :For supplying a cutting compound or coolant to the tool or tools with provision for controlling the coolant supplying means so that the coolant will be automatically supplied to the tool or tools at or about the beginning of the out and automatically shut oil at or about the completion of the cut.

i still further object is to provide a con struet-ion wherein the control of the tool, including. if desired, the feed of the tool during the cutting operation, as well as its automatic withdrawal from the worlr at the completion of the cut and its subsequent restora- 35 tion to cutting position and the control of the coolant supplying means, will be accom plished by the same mechanism.

t still further object is to provide an improved mechanism for controlling the feed oil a plurality of tools in a tool holder and the withdrawal of the tools from the Work and subsequent restoration thereof to cutting position. a s iecial object being to accomplish these results with an actuator in the form ot a cam engaged by a single follower which is conueci'cl to the tools.

.ln addf onal object is to provide for the control of the tool or tools of the work holder an actuating means carried in part by the tool holder and in part by the spindle of the machine. these parts being arranged so as to to accomplish the above results and preiembly also to provide a substantially zieontinmus valve controlled conduit for ply ct coolant into the tool holder and therefore to the tool or tools.

The above and other objects are attained by m invention which may be briefly summasirc consiiui' 1g in certain novel details of consti uCtlOll and combinations and arrangements of parts which will bedescribed in the specification and set forth in the appended claims.

In the accompanying sheets of drawings, Fig. l is a side elevation of a portion of a 1nachine tool, in the form of a lathe, which in this instance is adapted for boring and threading pipe couplings, portions of the machine not essential to an understanding of the invention being omitted, and a portion of the work holder, in the form of a chuck, being broken away and the coupling in the chuck being in section; Fig. 2 is a sectional View on an enlarged scale showing a portion of the tool holder with its tools, in this instance threading tools, the section being longitudinally ot' the tool holder substantially along the irregular line 22 of Fig. 3; Fig. 3 is a transverse sectional view substantially along the line of Fig. 2, a portion being broken away; Fig. 4 is a perspective view of the slide which supports one of the tools and which in turn is slidably supported in the tool holder; Fig. 5 is a similar View of a connecting member between the slide of Fig. 4 and the follower which is controlled by the actuator; Figs. 6, 7 and 8 are longitudinal sectional views through the tool. holders and through a portion of the coolant and tool controlling means supported by the spindle, Fig. 6 showing the parts in the relative positions which they occupy with the tools at or about the beginning of the out, Fig. 7 showing them at or about the completion oi the cut, and Fig. 8 showing them with the tools withdrawn from the work at or about the start of the return movement of the tool holder; Fig. 9 is a view partly in elevation and partly in section showing the tool holder and the work holding spindle, the latter and the collapsible or telescopic tool and coolant controlling means in the spindle being in section; Fig. 10 is a view on a larger scale showing the coolant and tool controlling means carried by the spindle with the parts collapsed and the ports open for the supplying of coolant to the tool holder during the cutting operations; Fig. 11 a similar view showing the parts extended and the coolant supplying ports closed, these parts now being in the relative positions which they occupy when the tool holder has traveled back a certain distance and the tools have been restored to cutting position; Fig. 12 is a detached view of the actuator which is carried by the tool holder, a part being in section; Fig. 13 is a sectional view of the forward end of one of the coolant and tool controlling members supported by the spindle; and Fig. 14 is-a sectional view substantially along the line 1 l1 l of Fig. 13.

Referring now to the drawings, 15 represents the bed of the machine tool, 16 the head, including a hollow spindle to be referred to presently and adaptedto be rotated by any suitable mechanism incorporated in the head, and 17 represents the main tool holding slide which may be and preferably is in the form of a turret mounted in the usual manner on a turret-saddle movable along the ways of the bed 15 toward and from the head 16. In this instance, the machine illustrated is for boring and threading pipe couplings of the same general character as that disclosed in my prior application Serial No. 89,518, filed February 20, 1926. Accordingly, the spindle is shown provided with a chuck 18 in which is mounted a coupling 19 adapted to be bored, threaded, faced and chamfered at its ends.

Then the machine is employed for boring and threading as well as for end-facing couplings, one face of the turret will be provided with a boring head, and another with a threading head, but as my invention operates the same for both heads, only one is herein illustrated, that being the threading head. This threading head is secured to the face of the turret through the medium of an adapter 20 and it includes a tool holding body 21 which may be attached to the adapter in any suitable manner. This tool holding body has a main portion which is substantially rectangular in shape, as illustrated in Fig. 3, and at the forward end it is provided with an annular, pilot-like extension 22 the forward or free end of which has a removable portion 22', the removable feature being for the purpose of assembly or replacing the actuator with an actuator having a different cam slot, as well as to form an internal shoulder to be referred to. The two tools 23, which in this case are threading tools, project from opposite sides of the body 21, these tools being substantially diametrically opposite each other and one being in advance of the other, as indicated in Figs. 1, 2, 6, 7 and 8. Both tools are movable laterally of the axis of the tool holder for the purpose of providing a feed since the coupling is both bored and threaded on a double taper illustrated in Fig. 1. The tools are mounted identically for sliding movement in the holder 21, the mounting for each tool including a substantially U-shaped slide 24, which slides are on opposite sides of a cam bar actuator to be referred to presently. On

one side of each slide is a tool receiving angular extension 25 which receives the inner end of the tool, as illustrated in Figs. 3 and 4, and the tools are held in place against this extension by screws 26. On opposite sides of the tool holding body a pair of plates 27 are provided which cover the machined openings provided to receive the tools and their slides. Each tool and its slide are adjustably connected by an adjustable screw 28 to a member 29 slidingly arranged between the legs of the forked slide 24. The screw 28 is held by a collar 30 from endwise movement with reference to the slide 24 and its inner end has threaded engagement with the member 29 so that by adjusting the screw the tool and its slide at are moved in or out with reference to the member 29 to suit the diameter of the work.

The tool body 21 is hollow throughout its length, the opening or bore, which is cylindrical in form, being designated 31. The rear end of this opening is closed by a plug 31 or otherwise so as to form a chamber for the coolant. this annular, axially extending bore is an actuator 32 which is movable relative to the holder 21 in an axial direction. This actuator has two oppositely disposed, flat, parallel faces 32 which are engaged by the two tool slides 24, and it has two rounded edges 32 which engage the inner cylindrical wall of the bore 31 (see Fig. 3). At its forward Slidably mounted in end, the actuator has a cylindrical enlargement 33 which has a sliding fit in the cylindrical bore 31,-this enlargement being hollow, as best illustrated in Fig. 12, for purposes to be referred to.

The actuator 32 has anirregular cam slot 34 which extends from its rear end forwardly 1 v toward but not entirely to the enlargement 33 at its forward end. This cam slot has par allel sides and it slidingly receives a follower 35, the opposite end portions of which are pivotally connected by screw pins 36 to the members 29 associated with the two slides 24. These members 29, since they connect the follower to the slides, which in turn support the tools, may be aptly referred to as slide and follower connecting members.

The actuator, in this instance, has what may be termed a three-fold function. First, it feeds the tools during the cutting operation,

one tool which bores or threads one-half the r coupling being moved outwardly and the other which bores or threads the other half of the coupling being moved inwardly. Secondly, the actuator is adapted to automatically withdraw the tools from the work at the end of the cutting operation. Thirdly,

it is adapted to automatically restore the tools to cutting position after the main tool holding slide has been retracted a certain or predetermined distance from the head and,

the tools are clear of the work. These a Fig. 8.

several results or functions are accomplished by the actuator by reason of its cooperation with certain parts supported by the spindle, as will be described presently.

At this point I will describe the shape of the cam slot and the shape of the follower which enable these results to be accom plished by the movements of the actuator 32 relative to the tool holding body 21. It will be observed that the cam slot has a main portion 3d with parallel side ed 'es formed on a continuous inclination the angle of which corresponds with the taper of the work. Near its forward end this cam slot has an offset, straight extension which is designated 3M, and between these two portions there are two cam faces 3d and 34. Furthermore, the inclined portion 3% of the cam slot has two relieved portions 3%? and 3 t The follower 35 has two opposite, parallel edges which engage the opposite sides of the inclined portion 34; of the cam slot, and both edges have relieved portions 35 and 35 (see Fig. (5).

At this point, the action of the follower and of the actuator will be described with reference to the peculiar and novel shapes which are given to the cam slot and actuator. Referring to Figs. 6, 7 and 8, in Fig. 6 the follower, tools and actuator are in the relative positions whico they occupy when the tools are about to start their cut. The actuator is now in its forwardmost position in the tool holding body 21 with its forward end abutting against a shoulder 37 formed by the inner end of the removable forward part of the pilot 2 of th tool holding body 21. At this time the follower is at the rear end of the inclined portion Sel of the cam slot of the actuator. As the tool holder now moves forard toward the head, the cutting begins while the actuator is held stationary in a manner to be described and during the cut-- ting operation the follower moves forwardly in the cam slot 34; to the position shown in Fig. T which shows the parts at the completion of the cut. As it 'ravels along this part of the cam slot, the forward tool 23 is moved outwardly. and the trailing tool is moved inwardly while cutting, thus cutting or form in g threads on the opposite tapered portions of the coupling. lVhen the follower and actuator reach the relative positions shown in Fig. 7. the forward end of the follower en gages the cam face 3d of the cam slot, the rear end of the follower now being opposite the relieved portion 3% of the slot. Slight further forward movement of the tool holder btuyond the position shown in Fig. '7 will earn the follmver to the position shown in Fig. 8, with the result that the tools are both withdrawn from the work piece or moved from the position shown in Fig. 7 to that shown in at this point in the cycle of operations the forward movement of the main tool holding slide ceases.

Thereupon the main tool holding slide is retracted, and during the main portion of the movement of retraction the tool holding body 21, actuator 32, follower 35 and tools 23 remain in the relative positions shown in F ig. 8 until the tools are clear of the work piece, whereupon, by the action of the parts of the tool controlling means supported by the spindle (the inner and outer hollow telescopic members 54 and 56 to be later referred to), during the major portion of the remainder of the retraction of the main tool slide, the actuator 32 is held stationary. This first causes the follower 35 to be cammed back into alignment with the inclined portion of the cam slot 34 or to the position shown in Fig. 7 by means of the cam face 34 of the cam slot. This automatically restores the tools to the position shown in Fig. 7, this being the position which they occupied at the finish of the cut, and then during the continned retracting movement of the main tool slide (the actuator 32 still being held sta tionary) the follower moves back to the rear end of the cam slot illustrated in Fig. 6, restoring the tools to the position which they occupied at the beginning of the out. When they reach this position the forward end of the actuator engages the shoulder 37 near the forward end of the pilot portion of the tool holding body, and during the remainder of the retracting movement of the main tool slide the tool holding body and all the parts carried by it, including the actuator, follower and tools, move as a unit.

I will next describe that portion of the mechanism. which is supported by and. extends through the hollow work spindle of the head, which spindle is designated 38, see Fig. 9.

At this point it might be mentioned that the complete machining of a coupling involves in addition to the boring and threading operations, the facing or the facing and chamfering of the ends of the coupling. This is accomplished by one or more tools 39 supported by the adapter 20, see Fig. 1, for facing and chamfering the outer end of the coupling, and by one or more tools 40 for facing and chamfering theinner end of the coupling. The tool or tools l0 are carried by a backfacing head 41 which is inside of the chuck 18 just forward of the spindle and it is carried by a sleeve 42 which extends entirely through the spindle and out beyond the rear end. The rear end of the sleeve 42 is attached to a slide 43 mounted on one or more guide arms l4 extending rearwardly from the head 16. This slide is adapted to be actuated by mechanism including a link 45, a lever havmg a segment 46 which engages a rack 47 carried by a bar 48 which is adapted to be moved forwardly to cause the tool or tools to function on the inner end of the coupling as the main tool slide moves forwardly. This is preferably accomplished by providing on the saddle carryi the turret an extension Y 49 with an eccentric 50 which when swung to the position shown in Fig. 1 is clear of the bar 48 and when swung downwardly will form an abutment for the bar 48 and thus move it forwardly and bring about the chamfering and facing of the inner end of the coupling. The back-facing attachment and all the parts associated therewith are adapted to berestored to their normal position by a spring 51.

This mechanism just described forms no necessary part of the-present invention but is referred to inasmuch as it includes the sleeve 42 through which extend certain important parts of my invention now to be described, the latter cooperating with the actuator to control the tools in the manner eX- plained above and also to supply coolant to the tool holder and therefore to the tools.

Taking up now this part of the invention, it will be observed that at the rear end of the head of the machine and at the outer end of the arm or arms 44 is an upstanding bracket 52 having a head with a bore, the bore being in line with the bore in the Work spindle 38. In the head of this bracket is secured a portion of a fitting 53 to which is secured the rear end of a hollow inner member 54 of a telescopic tool actuator and coolant supplying and controlling means which extends through and is supported by the work spindle. The inner member 54 which is stationary and eX- ten'ds only part way through the spindle, as illustrated in Fig. 9, has at its forward end a head forming a shoulder 55 '(see Fig. 10).

Slidable on and telescopic with respect to the inner member 54 (see Fig. 10) is an outer hollow member 56 which is adapted to extend the'remainder of the distance through the spindle, this member being supported and centralized in the sleeve 42 by means of a packing member 57 which is fitted tightly onto the member 56 somewhat near its forward end. The function of this packing member is not only to centralize the member 56 in the sleeve 42 but is to prevent the escape of coolant along the exterior of the member 56.

Between the ends of the outer member 56 there is an enlargement 58 and extending lengthwise of this enlargement are series of passageways 59 which terminate at their rear ends in ports 59 and at their forward ends open into the forward portion of the bore of the member 56 beyond the head having the shoulder 55 of the inner member 54.

Connected to the outer end of the inner 1nember 54 is a coolant supplying pipe 60 which may be connected to any suitable source of coolant under pressure, such as a pump. This coolant may be oil or other su1table liquid, such as a cutting compound. About midway of the ends of the inner member 54 are a series of ports 61 which, when the parts 54 and 56 are collapsed or fully contracted, as in Fig. 10, are in registration wlth the ports 59 of the outer member 56.

At the forward end of the outer member 56 is a head 62 which carries a pair of fingers in the form of latches 63 which are pressed yieldingly apart by a spring 64. These fingers are pivoted at 65 internally of the head 62 between spaced webs 65 arranged so as not to interfere with the free flow of coolant through the said head, and they project forwardly beyond the head, as best illustrated in Figs. 6 and 13. The forward ends of the fingers are tapered, as illustrated, and when the fingers are in their normal position as held by the spring 64, they are adapted to enter the hollow enlargement 33 at the forward end of the actuator 32, the parts being so proportioned that the forward end of the outer member 56, including its head 62, may slide into the removable end 22 of the pilot iortion of the tool carrying body 21; The forward ends of the fingers have the equivalent of hooks which are adapted to engage behind a shoulder 33* of the enlargement 33 of the actuator, and thus form a positive connection with the actuator, at which time the outer telescopic member 56 and the actuator are end to end, as illustrated in Fig. 6, the opening formed in the hollow enlargement 33 of the actuator forming a continuation of the conduit or bore within the outer telescopic member 56 so that coolant flowing through the latter will flow through the enlargement of the actuator and may pass through the bore of the tool holding body 21 on opposite sides of the actuator and may pass by way of passageways 66 (see Fig. 3) under the plates .27 and by additional passageways 67 therethrough directly to the tools where they engage the work. The construction of the tool holder is such that coolant thus supplied to the holder will fill or substantially fill the inner bore of the tool holding body and will flow substantially equally through the passageways to the tools so as to cool them and facilitate the cutting in the desired manner.

Thefunction and mode of operation is as follows: When the main tool slide is fully retracted, the telescopic member is extended as in Fig. 11. At this time the ports 61 and 59 are out of registration and separated a considerable distance, as will be seen by reference to Fig. 11, and the hooks or fingers 63 will project slightly beyond the forward end of the spindle. As the main tool slide moves toward the head, the pilot of the tool carrying body 21 enters the bore of the work spin dle and slidingly engages the inner wall of the sleeve 42 which in turn is held centrally in the bore of the work spindle. At the same time the extension 22 at the forward end of the pilot portion of the tool holder body 21 slides onto the head 62 at the forward end of the outer telescopic member 56 and the hooked ends of the fingers snap behind the shoulder 33 of the actuator 32. it will be remembered that at this time the actuator 32 and the follower 35 occupy the positions in the tool holding body 21 shown in Fig. 6. When the engagement takes place between the outer telescopic member 56 and the forward end 33 of the actuator 32, as explained, the continued forward movement of the main tool slide simply results in moving the outer telescopic member 56 backward into the spindle without changing the relative positions of the tool holding body 21 and the actuator 32. This telescopic IHOVQIIIGIll; of the outer member 56 relative to the inner member 54: continues until the inner or rear end of the outer member 56 abuts against the fitting 53, the engagement of these parts being illustrated in Fig. 10. Just before this engagement takes place the ports 59 and 61 come partly into registration and coolant begins to flow from the inner telescopic member 54 through these ports and through the passageways 59 into the forward portion of the outer telescopic member 56 and there fore into the tool holder. This flow of coolant is started just before the tools begin to out. As soon as the engagement takes place between the outer telescopic member 56 and the fitting, as just stated, the forward 1novement of the actuator 32 toward the head is stopped and likewise the telescopic sliding movement of the members 54 and 56 stops. This results in the travel of the follower 35 along the cam slot of the actuator 32 and therefore produces the feed of the tools, the cutting operation starting soon after the feed begins.

The main tool slide continues its forward movement toward the head and throughout the cutting operation the actuator is held stationary by the forward end of the outer telescopic member 56, the flow of coolant continuing since the ports during the entire cutting operation are in full registration. 'lhroughout this period, 1. e., throughout the period of cutting, the tools have a uniform feed in a lateral direction.

As soon as the cutting operation is completed, the follower 35 reaches the position shown in Fig. 7, whereupon the follower is cammed to the position shown in Fig. 8, cansing the automatic withdrawal of the tools from the work. At this point the movement of the main tool slide is stopped and reversed (either automatically or through hand operation). During this backward or reverse movement of the tool slide, due to the fact that the fingers 63 are interlocked with the forward end of the actuator, the outer telescopic member 56 is now moved forward- 1y of the work spindle, immediately stopping the flow of coolant and the forward travel of the outer telescopic member continues until a shoulder 68 just forwardly of the ports 59 engages the shoulder 011 the head at the forward end of the inner telescopic member 54, this occurring when the two telescopic members are in the relative positions shown in Fig. 11. During the forward movement of the outer telescopic member 56 just described, and before the engagement of the shoulders takes place, the tools withdrawn from the work piece are being retracted and when the engagement just described between the shoulders 68 and 55 takes place the tools are clear of the work piece.

When the engagement between the shoulders 68 and 55 takes place and the forward movement of the outer telescopic member 56 in the spindle is, therefore, stopped, the movement of the actuator 32 is temporarily stopped, with the result that the follower 35 is cammed by the cam face .34 from the position shown in Fig. 8 to the position shown in Fig. 'i'. For a period the actuator 32. is held stationary during the retracting movement of the main tool slide, this continuing until the follower reaches the position shown in Fig. 6, in which event the tools are moved from the position shown in Fi 7 to that shown in Fig. 6 and are ready for the next cutting operation. At this point the inner end of the actuator 32 abuts against the shoulder 37 formed by the extension 22' of the pilot portion of the tool holding body 21. By reason of this engagement the actuator can no longer move backward through the pilot portion of the tool holding body, and when the pull onthe connection afforded by the fingers 63 between the actuator and the outer telescopic member 56 reaches a predetermined value the connection is broken by the hook-shaped ends of the fingers being forced inwardly against the pressure of the spring 64. After a short further backward movement of the tool slide, the latter is stopped and the machine is ready for the next operation on another work piece.

I prefer to provide suitable means for yieldingly holding the actuator 32 in its forwardmost position in the tool holding body 21 (Fig. 6) and in its rearwardmost position in the body (Fig. 8), and this is preferably accomplished by means of a detent 21 carried by the body 21 adapted to engage two properly positioned notches 32 and 32 in the actuator 32. In the construction illustrated, the detent 21 is pressed yieldingly inward by a spring 21 the detent and the spring being retained by a screw plug 21 in a radially disposed opening provided in the body 21, as illustrated in Figs. 2, 6, 7and 8 of the drawings. This detent is useful in preventing accidental movement of the actuator and particularly in holding the actuator against movement when during the forward motion of the main tool slide the parts p v gagement with the forward end of the actuator. Likewise, it prevents premature disengagement between the actuator and the fingers when the parts are approaching the relative positions shown in Fig. 6 during the 0 retraction of the main tool slide, that is to say, it prevents disengagement between the actuator and the fingers until the shoulders 68 and engage when the parts are in the positions shown in Fig. 11.

Thus it will be seen that as the main tool slide moves toward the head and work piece, interlocking engagement first occurs between the actuator carried by the tool holding body and that part of the actuator and coolant supplying means extending through and sup portednby the spindle. Then the latter is telescoped by the further movement of the main tool slide toward the head and just prior to the time that the tools reach cutting position the coolant begins to flow and the telescopic movement as well as the movement of the actuator is stopped, it being understood that there is now a continuous passageway for the coolant from the telescopic members past the fingers into the hollow enlargement at the forward end of the actuator and into the tool holding body so that both tools will be flooded with coolant. It will be understood also that at this time the two telescopic members and the actuator form a substantial ly continuous member held stationary by the abutting engagement between the rear end of the outer telescopic member 56 and the fitting 53, permitting a uniform feed of both tools to take place. Likewise, it will be understood that immediately following the completion of the cut the engagement between the rearwardly moving follower and the now stationary actuator 32 forces the follower to a position such as to withdraw the tools from the work, and upon the reversal of the movement of the main tool slide the flow of lubricant is cut off by reason of the fact that the actuator 32 pulls the outer telescopic member 56 forwardly, this continuing until the shoulder 68 engages the shoulder 55 (see Fig. 11). This again stops the movement of the actuator 32, resulting in the tool being automatically moved outwardly The actuator is then held stationary until the tools are again restored to cutting position, whereupon the connection between the actuator 32 and the outer telescopic member 56 is broken just prior to the end of the retracting movement of the main tool slide.

' Although I have illustrated my invention for the threading operation, it was previously stated that the invention has utility for other cutting operations such, for example, as when the boring head is utilized to bore on a double taper opposite halves of the couling. In that event, of course, boring tools are substituted for the threading tools, but

in both instances the mechanism herein described operates in precisely the same manner. My invention, in some of its aspects, may find utility also in other types of machine tools and, therefore, I do not wishto limit myself to a machine tool adapted for machining work on couplings.

It will be understood that the inclination of the cam slot of the actuator 32 will depend upon the degree of taper to be given to the couplings, the construction being such that one actuator in the tool carrying body 21 may be substituted for another to suit the taper which the coupling is to have.

Having thus described my invention, what I claim is:

1. In a machine tool, work and tool holding members movable relatively toward and away from each other, the tool holding member having a movable tool and carrying a movable tool actuator, and means independent of the tool holder engageable with the actuator to form a separable positive connection therewith during each cycle of operations.

2. In a machine tool, Work and tool holding members movable relatively toward and away from each other, the tool holding member having a movable tool and a movable tool actuator, the work holding member having means for engaging the actuator to hold it stationary during certain portions of the relative movements between the work and tool holding members, said engagement being terminable when subjected to a predetermined pull.

3. In a machine tool, work and tool holding members movable relatively toward and away from each other, the tool holding member having a movable tool and a movable tool actuator, and the work holding member having yieldable means for engaging the actuator to hold it stationary during certain predetermined movements between the work and tool holding members and releasable from the actuator when subjected to a predetermined pull.

4. In a machine tool, a hollow rotary spindle adapted to support a work piece,

and atool holder having a movable tool, the

spindle and tool holding member being relatively movable toward'and away from each other, the tool holding member having a tool shifter and the spindle having extensible and contractible means serving to engage and actuate the tool shifter.

5. In a machine tool, a hollow rotary spindle adapted to support a work piece, a tool holder having a tool and a tool actuator, the spindle and tool holder being relatively movable toward and from each other, and "the spindle having extensible and contractible means extending therethrough engageable with the actuator.

6. in a machine tool, a hollow spindle adapted to support a work piece, a tool holder having a tool and an actuator therefor, an extensible and contraotible means extendi through the spindle and having me for forming a positive connection with the actuator.

7. la a machine tool, a rotary hollow spindle for supporting a work piece, a tool holder havin a. movable tool and a tool actuator, and means for automatically retr-acting the tool from the work piece at the completion of the cut and for automatically restoring it to cutting position when the spindle and tool holding members are moved rel atively away from each other a predetermined amount, said means comprising a telescopic member in the hollow spindle having means for forming a positive connoel-ion with the actuator which connection is separable when subjected to a predetermined pull.

in a machine tool, a tool carrying member having a movable tool, an actuator for shifting the same and provided with camming portions, and a follower connected with. the tool to shift the same and engaging the cumming portions, the camming porions including a part for imparting a lateral eding motion and a part for rocking the follower to withdraw the tool from the work.

A. tool holder for a machine tool comprising a body adapted to receive a tool, a follower adapted to be connected with the tool to shift the same, an actuator having cam portions which the follower is adapted i to engage and including a, portion for laterally feeding the tool and portions for rocking the follower to withdraw the tool from the work and for subsequently moving it toward cutting position.

10. A tool holder for machine tools comprising a tool carrying body having a pair of movable tools, an actuator in the body, and a single follower engaging the actuator and connected with both tools to shift said tools in opposite directions.

ll. in a machine tool, a rotatable hollow work holding spindle, a tool slide movable to ard and from the same, a back facing attachment including sleeve extending through the spindle and supported thereby, and tool controllmg means extending through said sleeve.

152. la a machine tool, relatively movable work and tool holding members, a device car ried by the tool holding member and having operative connection with the tool, said device being movable relative to the tool holdmcmber and constituting the tool feeder during the cutting operation, a retractor of the tool at the completion of the cutting operation, and a restorer of the tool to cutting position, and means to automatically actuate said device to cause the feeding, rctracting and restoring of the tool.

13. In a machine tool, work and tool holding members relatively movable toward and away from each other, a device movably supported by the tool holding member and connected to the tool and constituting a tool feeder, a tool retractor and a tool restorer, and means operatively associated with said device so as to automatically cause it and the tool holding member to move relatively during relative movement between the work and tool holding members both toward and away from each other.

ll. In a machine tool, work and tool holding members relatively movable toward and away from each other, a device movably supported by the tool holding member and 0011- nected with the tool and constituting a tool feeder and a tool collapser during relative movement between the tool and work holding members in one direction and a tool restorer during relative movement between the work and tool holding members in the opposite direction, and means acting on said device to hold it stationary during portions of said relative movements in both directions.

15. In a machine too-l, work and tool holding members movable relatively toward and away from each other, a cam member movably supported by the tool holding member and operatively connected with the tool and constituting an automatic tool feeder, tool retractor and tool restorer, and means acting on said cam member to cause it and the tool holding member to be moved relatively during relative movements between the work and tool holding members in both directions.

16. In a machine tool, work and tool holding members movable relatively toward and away from each other, a cam member connected with the tool and movable longitudinally of the tool holding member and c011- stituting an automatic tool feeder, tool collapser and tool resto-rer, and means acting on said cam member to automatically cause relative longitudinal movement between it and the tool holding member during relative movement between the work and tool holding members in both directions.

17. In a machine tool, a rotary spindle and a tool holding member relatively movable toward and away from each other, a device constituting an automatic tool feeder, tool collapser and tool restorer movably carried by the work holding member and connected with the tool, and means extending through the spindle for acting on said device to cause it and the tool holding member to be moved relatively during relative movements be tween the spindle and tool holding member in both directions.

18. In a machine tool, a work spindle and a tool holding member relatively movable toward and away from each other, a device constituting an automatic tool feeder, tool collapser and tool restorer connected with the tool and movable longitudinally of the tool holding member, and means extending through the spindle and acting on said device to cause relative longitudinal movement between said device and the tool holding member during relative movements between the spindle and tool holding member in both directions.

19. In a machine tool, tool and work holding members relatively movable toward and from each other, a tool actuator carried by the work holding member and operatively connected with the tool and serving as a tool feeder, a tool retractor and a tool restorer,

and means engageable with the actuator and serving to hold the same stationary during a portion of the relative movement of the Work 1 and tool holding members toward each other and serving to hold the same stationary during a predetermined relative movement be tween said members in the opposite direction after they have moved apart a predetermined distance.

In testimony whereof, I hereunto afliX my signature.

FRED H. BOGART. 

